Adds rcmdsh() -- rcmd-alike using rsh (or specified shell).

2 files changed, 122 insertions, 2 deletions

diff --git a/src/lib/libc/net/Makefile.inc b/src/lib/libc/net/Makefile.inc
index e71a0f99fe..708684876a 100644
--- a/src/lib/libc/net/Makefile.inc
+++ b/src/lib/libc/net/Makefile.inc
@@ -1,4 +1,4 @@
-#       $OpenBSD: Makefile.inc,v 1.6 1996/08/19 08:28:32 tholo Exp $
+#       $OpenBSD: Makefile.inc,v 1.7 1996/08/22 20:11:19 millert Exp $
 
 # net sources
 .PATH: ${.CURDIR}/arch/${MACHINE_ARCH}/net ${.CURDIR}/net
@@ -10,7 +10,7 @@ SRCS+=	gethostnamadr.c getnetbyaddr.c getnetbyname.c getnetent.c \
         ipx_addr.c ipx_ntoa.c \
         iso_addr.c linkaddr.c ns_addr.c ns_ntoa.c nsap_addr.c rcmd.c recv.c \
         res_comp.c res_debug.c res_init.c res_mkquery.c res_query.c \
-        res_send.c send.c sethostent.c ethers.c
+        res_send.c send.c sethostent.c ethers.c rcmdsh.c
 
 # machine-dependent net sources
 # m-d Makefile.inc must include sources for:
diff --git a/src/lib/libc/net/rcmdsh.c b/src/lib/libc/net/rcmdsh.c
new file mode 100644
index 0000000000..47b200ed68
--- /dev/null
+++ b/src/lib/libc/net/rcmdsh.c
@@ -0,0 +1,120 @@
+/*      $OpenBSD: rcmdsh.c,v 1.1 1996/08/22 20:11:20 millert Exp $      */ 
+
+/*
+ * This is an rcmd() replacement originally by 
+ * Chris Siebenmann <cks@utcc.utoronto.ca>.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char *rcsid = "$OpenBSD: rcmdsh.c,v 1.1 1996/08/22 20:11:20 millert Exp $";
+#endif /* LIBC_SCCS and not lint */
+
+#include      <sys/types.h>
+#include      <sys/socket.h>
+#include      <sys/wait.h>
+#include      <signal.h>
+#include      <errno.h>
+#include      <netdb.h>
+#include      <stdio.h>
+#include      <string.h>
+#include      <pwd.h>
+#include      <paths.h>
+
+/*
+ * This is a replacement rcmd() function that uses the rsh(1)
+ * program in place of a direct rcmd(3) function call so as to
+ * avoid having to be root.  Note that rport is ignored.
+ */
+int
+rcmdsh(ahost, rport, locuser, remuser, cmd, rshprog)
+        char **ahost;
+        u_short rport;
+        char *locuser, *remuser, *cmd;
+        char *rshprog;
+{
+        struct hostent *hp;
+        int cpid, sp[2];
+        char *p;
+        struct passwd *pw;
+
+        /* What rsh/shell to use. */
+        if (rshprog == NULL)
+                rshprog = _PATH_RSH;
+
+        /* locuser must exist on this host. */
+        if ((pw = getpwnam(locuser)) == NULL) {
+                (void) fprintf(stderr, "rcmdsh: unknown user: %s\n", locuser);
+                return(-1);
+        }
+
+        /* Validate remote hostname. */
+        if ((hp = gethostbyname(*ahost)) == NULL) {
+                herror(*ahost);
+                return(-1);
+        }
+        *ahost = hp->h_name;
+
+        /* Get a socketpair we'll use for stdin and stdout. */
+        if (socketpair(AF_UNIX, SOCK_STREAM, 0, sp) < 0) {
+                perror("rcmdsh: socketpair");
+                return(-1);
+        }
+
+        cpid = fork();
+        if (cpid < 0) {
+                perror("rcmdsh: fork failed");
+                return(-1);
+        } else if (cpid == 0) {
+                /*
+                 * Child.  We use sp[1] to be stdin/stdout, and close sp[0].
+                 */
+                (void) close(sp[0]);
+                if (dup2(sp[1], 0) < 0 || dup2(0, 1) < 0 || dup2(0, 2) < 0) {
+                        perror("rcmdsh: dup2 failed");
+                        _exit(255);
+                }
+                /* Fork again to lose parent. */
+                cpid = fork();
+                if (cpid < 0) {
+                        perror("rcmdsh: fork to lose parent failed");
+                        _exit(255);
+                }
+                if (cpid > 0)
+                        _exit(0);
+
+                /* In grandchild here.  Become local user for rshprog. */
+                if (setuid(pw->pw_uid)) {
+                        (void) fprintf(stderr, "rcmdsh: setuid(%u): %s\n",
+                                       pw->pw_uid, strerror(errno));
+                        _exit(255);
+                }
+
+                /*
+                 * If remote host is "localhost" and local and remote user
+                 * are the same, avoid running remote shell for efficiency.
+                 */
+                if (!strcmp(*ahost, "localhost") && !strcmp(locuser, remuser)) {
+                        if (pw->pw_shell[0] == '\0')
+                                rshprog = _PATH_BSHELL;
+                        else
+                                rshprog = pw->pw_shell;
+                        p = strrchr(rshprog, '/');
+                        execlp(rshprog, p ? p+1 : rshprog, "-c", cmd,
+                               (char *) NULL);
+                } else {
+                        p = strrchr(rshprog, '/');
+                        execlp(rshprog, p ? p+1 : rshprog, *ahost, "-l",
+                               remuser, cmd, (char *) NULL);
+                }
+                (void) fprintf(stderr, "rcmdsh: execlp %s failed: %s\n",
+                               rshprog, strerror(errno));
+                _exit(255);
+        } else if (cpid > 0) {
+                /* Parent. close sp[1], return sp[0]. */
+                (void) close(sp[1]);
+                /* Reap child. */
+                (void) wait(NULL);
+                return(sp[0]);
+        }
+        /*NOTREACHED*/
+}